Can't place cushions inside of barrier

Issue Summary:
Cushion entities fail to recognize the top surface of Barrier blocks as a valid placement vector, preventing manual placement completely. Additionally, when using Operator Items (such as the Debug Stick) or administrative commands to force-modify block states, the cushion clips directly inside the barrier block space, completely ignoring standard solid block collision logic.

Technical Details:
In Java Edition 26.3 Snapshot 9, the new Cushion feature behaves as a placement-dependent entity/block. While standard mechanics allow cushions to align horizontally along any full, flat block face, they treat the minecraft:barrier block as a completely non-solid or void space during the item placement raycast.

Furthermore, if a player utilizes Creative mode Operator Items or commands to force the cushion and barrier into the same coordinate space, the cushion clips entirely INSIDE the barrier block volume. Instead of being properly displaced or throwing a placement error, the cushion remains trapped inside the invisible solid block, indicating an unhandled collision desynchronization between cushions and operator-tier blocks.

Steps to Reproduce:

1. Launch Minecraft Java Edition in 26.3 Snapshot 9 (Vanilla profile).

2. Create a new Creative world with cheats enabled, ensuring you have access to the Operator Items tab.

3. Obtain the required items: /give @s barrier, /give @s color_cushion(Replace “color” into red, white, black…), and /give @s debug_stick.

4. Place a single Barrier block on the ground.

5. Attempt to manually place the Cushion on the top face of the Barrier block (Observed Result A).

6. Use the Debug Stick or coordinates commands to force a cushion state directly inside the exact coordinates (~ ~ ~) occupied by the solid Barrier block.

7. Observe the physical position of the cushion relative to the invisible barrier walls (Observed Result B).

Observed Results:

• Result A: The cushion cannot be placed onto the barrier block surface manually. The item interaction fails entirely.

• Result B: When using operator tools or commands, the cushion successfully populates directly inside the barrier block, causing total visual clipping and ignoring the barrier's solid volume.

Expected Results:

• Barrier blocks possess solid collision bounds; therefore, cushions should cleanly place on top of them just like any other solid block.

• When manipulated via operator items, cushions should respect the solid volume of a barrier block and should not clip inside its internal coordinate structure.